Tamriel is elvish for Dawn's Beauty. So what would other races call it? Argonians, Nords and Khajiit have very different languages to the Mer ones. The only other name for Tamriel I know of is Taazokaan, which is Dragonish, which might've be used by ancient Nords, depending on what phrases and words survived (like for instance "Unslaad Vignir" and "Thu'um" still being used by modern Nords) and the widespreadedness of Dragon Language (Dragon Priests were the only ones who were allowed to call Dragons Dovah, suggesting Dragon Language wasn't known fluently to the masses).

Arena could be one. At least that's what it is called in game as a metaphorical reference. Don't know about other languages.

We Fadomai's children call it Nirni with great reverence.

This one believes you misinterpreted the thread, yes? Lorkaj help you when you mistake this continent for all of Nirni!

Arena is all of Mundus. Isn't Nirn Ehlnofex for the word Arena?

Which is why I was careful to include "could be" . http://www.imperial-library.info/content/pocket-guide-empire-third-edition-arena-supermundus-tapestry-heaven, I can see my mistake. :3 Lorkaj help me!

But M'eyap loves it a lot more than any other continent, so M'eyap hoped no one would notice

Aedragraveyard
Not-Akavir

The argonians probably call it something long and hard to pronounce.

TAM RUGH